Many types of electrochemical cells utilize an ionically conductive medium to support electrochemical reactions within the cell. For example, a metal-air electrochemical cell system may comprise one or more cells, each having a fuel electrode serving as an anode at which metal fuel is oxidized, and an air breathing cathode at which oxygen from ambient air is reduced. Such cells may also comprise an ionically conductive medium, such as a liquid electrolyte solution, to communicate the oxidized/reduced ions between the electrodes. For example, see U.S. Patent Publication No. 2009/0284229, now U.S. Pat. No. 8,309,259, incorporated in its entirety herein by reference. In some electrochemical cell systems comprising a plurality of electrochemical cells, the ionically conductive medium may be shared by multiple cells. For example, the liquid electrolyte solution may flow in series from one cell to another, such as is described in U.S. Patent Publication 2010/0316935, incorporated herein in its entirety by reference. In other electrochemical cell systems, the ionically conductive medium may be shared by multiple cells, but may flow partially in parallel. In still other electrochemical cell systems, the ionically conductive medium might not flow at all, but may instead be stagnant, or merely be agitated within a confined area between the electrodes.
Regardless of any movement of the ionically conductive medium, in conventional systems utilizing an air electrode, the air electrode defines a boundary wall for confining the ionically conductive medium within the electrochemical cell system. This is to say that the air electrode is typically sealed to the exterior of the housing, forming an ionically conductive medium impermeable barrier. A drawback to such conventional systems, however, is that if the seal between the air electrode and the housing were to fail, or if a leak were to form in the air electrode itself, a liquid ionically conductive medium would no longer be confined within the electrochemical cell, which may result in complete failure of the cell, the need to replace the ionically conductive medium, harm to the environment around the electrochemical cell, and so on. Also, in most designs, replacement of the air electrode is a difficult task, as the ionically conductive medium must be drained so that the used gaseous oxidant reduction electrode can be removed. It may therefore be appreciated that immersing the air electrode, along with a housing forming air space therein, into the ionically conductive medium may prevent the such complete failures, and may simplify replacements of air electrodes. An example of a conventional immersible air electrode is shown, for example, in U.S. Pat. No. 5,011,747, incorporated in its entirety herein by reference.